1. Field of the Invention
This invention pertains generally to a needle guide, and more particularly to a needle guide for attachment to a medical instrument such as an imaging probe.
2. Description of Related Art
Pelvic inflammatory disease affects nearly 1 million women in the United States annually, and approximately 85,000 of these women eventually have pelvic abscesses. Left untreated, pelvic abscesses are associated with acute morbidity, adhesion formation, impaired fertility, and chronic pelvic pain. Although many pelvic abscesses respond to antibiotic therapy, surgery is often needed when antibiotics fail. However, laparotomy for pelvic abscesses is one of the more technically difficult gynecologic procedures and has associated surgical and anesthetic risks, hospitalization costs, and prolonged recovery times. The definitive surgical treatment of a total hysterectomy and bilateral salpingo-oophorectomy is highly effective. However, the surgical treatment leaves patients infertile and devoid of ovarian hormones, which are major problems in the young premenopausual women who tend to be affected by pelvic abscesses. Total abdominal hysterectomy is the alternative to failed aspiration or drainage of these abscesses.
Pelvis Abscess may also be due to a number of other etiologies. Patients with appendicitis, diverticulitis or Crohn's disease may develop pelvis abscesses. Laparatomy is highly effective in the treatment of these pelvic abscesses. However, laparotomy is associated with both anesthesia and surgical risks, and prolonged recovery time.
Over the past decade, percutaneous image guided drainage of pelvic abscesses has shown to be an effective alternative to surgical techniques [1]. Various approaches have been advocated for drainage of these abscesses, including the transabdominal route, the transgluteal route [2], the transrectal route [3, 4] and the transvaginal route [5, 6]. CT or sonography has been used to guide the transabdominal and the transgluteal abscess drainage. Only sonography is used for guidance of transrectal or transvaginal abscess drainage. However, for sonographically guided transrectal or transvaginal trocar method of needle placement, the use of a punctured channel that is not open to allow the catheter to be free is a technical limitation for all current endorectal and endovaginal transducers.
Therefore, there have been modifications of different transrectal or transvaginal ultrasound probes to allow catheter placement. These have included the use of a catheter, which is placed through a peel-away sheet or catheters that are placed into a groove on the ultrasound probe and are fixed with rubber bands. These allow trocar catheter placement for transrectal or transvaginal drainage [7-10].
Transrectal and/or transvaginal abscess drainage using sonographic technique has been shown to be an effective method in drainage of pelvic abscesses. While CT was previously the method that was utilized for drainage of these abscesses via the transgluteal and/or the transabdominal route, there have been a number of different manuscripts that have described the transrectal or transvaginal sonographic guidance of deep pelvic abscess. [5-10]
When using the transrectal or transvaginal route, aspiration alone has been shown to be as successful when compared with catheter placement. For instance, Lee [7] reported an overall success rate of 86%, using aspiration alone or 86% success rate for catheter placement. Van Sonnenberg [6] has shown an 88% success rate in patients with aspiration alone, compared to 83% with catheter placement. However, patients with aspiration alone may have smaller fluid collections, less loculations or less viscous fluid than those in which catheters are placed. Catheter placement allows repeated flushing of larger abscesses to help breakdown loculi and decrease the viscosity of the abscess contents.
With the Seldinger technique, a needle is placed, and then a guide wire is placed through the needle after removal of the needle stylet. Thus the needle, the needle guide and the ultrasound probe are then removed. The guidewire is kept in place and the rest of the technique may be guided by fluoroscopy or by ultrasound. However, there may be difficulty in catheter placement via the Seldinger technique when using the endovaginal route. This is because of the difficulty with buckling of the guidewire when dilators or catheters are placed through the thick vaginal musculature.
Thus, the invention relates to providing a needle guide for attachment to a sonographic transducer, which allows the probe and needle guide to be detached and removed from the needle or trocar catheter and removed from the patient while the needle or trocar catheter remains in place within the abscess cavity. This will allow for a single step for catheter placement into a pelvic abscess using either the endovaginal or endorectal route.